### 4A.13

Posted:

**Wed Feb 05, 2020 4:47 pm**A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in 0.200 L of solution in the calorimeter (q 5 23.50 kJ), resulting in a temperature rise of 7.32 8C. In a subsequent experiment, 100.0 mL of 0.200MHBr(aq) and 100.0 mL of 0.200M KOH(aq) were mixed in the same calorimeter and the temperature rose by 2.49 8C. What is the change in the internal energy?

For the second part where you plug in the Ccal calculated into the q=-Ccal(delta T) in order to find q or delta U, why is there a negative sign in front of Ccal?

For the second part where you plug in the Ccal calculated into the q=-Ccal(delta T) in order to find q or delta U, why is there a negative sign in front of Ccal?